Door return and check mechanism

ABSTRACT

A DOOR RETURN MECHANISM INCLUDING DOOR CHECKING MEANS FOR SLOWING THE RATE OF RETURN AS THE DOOR APPROACHES ITS CLOSED POSITION. THE RETURN MECHANISM INCLUDES A COIL SPRING WHICH, IN ADDITION TO ITS DOOR RETURN FUNCTION, SERVES TO HOLD THE DOOR OPEN WHEN THE LINKAGE IS MOVED TO AN OVER-CENTER POSITION. THE CHECKING MEANS COMPRISES A DISC-TYPE BRAKE, THE BRAKE SURFACES OF WHICH ARE MAINTAINED IN FRICTIONAL ENGAGEMENT BY AN ADJUSTABLE SPRING FORCE. THE BRAKE IS MOUNTED ACROSS A PARALLEL LINKAGE WHICH IS ARRANGED TO PROVIDE A GREATER ANGULAR MOVEMENT OF THE BRAKE SURFACES AND HENCE A GREATER BRAKING EFFECT AS THE DOOR APPROACHES THE DOOR FRAME.

y 1971 c. e. PIERIE 3,579,709

DOOR RETURN AND CHECK MECHANISM Filed Dec. 24, 1969 3 Sheets-Sheet 1 FIGI.

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May 25, 1971 c. G. PIERIE DOOR RETURN AND CHECK MECHANISM Filed Dec. 24, 1969 5 Sheets-Sheet I FIGS.

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DOOR RETURN AND CHECK MECHANISM Filed Dec. 24, 1969 3 Sheets-Sheet 5 INVENTOR; CHARLES G. PIERIE him/ W ATTYS- United States Patent Int. Cl. Ef 1/08 US. Cl. 16-65 12 Claims ABSTRACT OF THE DISCLOSURE A door return mechanism including door checking means for slowing the rate of return as the door approaches its closed position. The return mechanism includes a coil spring which, in addition to its door return function, serves to hold the door open when the linkage is moved to an over-center position. The checking means comprises a disc-type brake, the brake surfaces of which are maintained in frictional engagement by an adjustable spring force. The brake is mounted across a parallel linkage which is arranged to provide a greater angular movement of the brake surfaces and hence a greater braking effect as the door approaches the door frame.

The present invention relates generally to door return mechanisms and relates more particularly to an improved door return mechanism having a novel door checking means which may be easily adjusted to provide the desired checking effect.

A wide variety of door return mechanisms is presently in use, ranging from the simple coil spring to the complex mechanisms incorporating electric eyes used in commerical buildings. The present invention is directed to a low-cost spring-actuated mechanism which overcomes the problems of conventional spring-powered returns.

The conventional spring-actuated door return has a number of drawbacks, the most notable being the tendency to slam the door upon a person passing through. This is especially annoying if one is burdened with packages and unable to fend off the accelerating door. An additional disadvantage is the lack of effective means of adjusting the closing force applied to the door by the spring. Since doors of different size and weight require different closing forces, the lack of sensitive adjustment results in a pronounced slamming of the door should the spring be too powerful, or the failure of the door to close at all if the spring is too weak, especially if wind is a factor. It is thus frequently necessary to either replace the spring or the entire mechanism in an effort to achieve a reasonably satisfactory door closing action.

A further disadvantage of most conventional devices is their restriction of the permissible door opening to a position only slightly beyond 90 from the closed position. Since the usual device is of the linearly extendable type, any attempt to open the door beyond approximately 90 can result in serious damage to the door hinges as well as the closing device. Such damage is frequently caused by wind, especially with storm doors.

A further disadvantage of most conventional devices is their faliure to provide means for disengaging or reversing the spring force to hold the door in a fully open position.

In the present invention, the door return comprises a spring actuated linkage including a braking mechanism which is adjustable to permit the varying of the braking force. The braking mechanism is a disc-type friction brake which is mounted on the linkage so that a relatively large angular rotation of the brake takes place during a relatively small angular movement of the door as the door approaches its closed position. The braking force is thus maximized when most needed to prevent the slamming of the door. When the door is fully opened, the linkage 3,579,709 Patented May 25, 1971 reaches an over-center position at which the effect of the closing spring is reversed to hold the door open.

It is accordingly a first object of the present invention to provide a door return mechanism including a check means for effectively preventing the slamming of the door against the door frame.

A further object of the invention is to provide a door return mechanism as described wherein the check means provides an increased braking effect as the door approaches the door frame.

An additional object of the invention is to provide a door return mechanism as described wherein the check means may be readily adjusted to vary the effective return force applied to the door.

A still further object of the invention is to provide a door return mechanism as described which permits a opening of a door and which provides door control throughout the 180 opening range.

Another object of the invention is to provide a door return mechanism as described having an over-center posi tion which serves to hold the door in the fully open position.

A further object of the invention is to provide a door return mechanism as described of a relatively simple, easily fabricated construction and which may be readily installed without special tools or training.

Additional objects and advantages of the invention will be more readily apparent from the following detailed description of embodiments thereof when taken together with the accompanying drawings in which:

FIG. 1 is a plan view showing a door return and check mechanism in accordance with the present invention installed upon a conventional door and door frame with the door shown in the closed position;

FIG. 2 is a side elevational view of the door return and check mechanism illustrated in FIG. 1;

FIG. 3 is a sectional view taken along line 3-3 of FIG. 1 showing details of the check mechanism;

FIG. 4 is an exploded perspective view of several of the elements of the check mechanism;

FIG. 5 is a plan view of the door return and check mechanism of FIGS. 1-4 shown with the door opened at the over-center position, and indicating in broken lines the manner in which the door is held open by the mechanism 180 from the closed position;

FIG. 6 is a plan view of a modified form of door return and check mechanism shown mounted on a conventional door and door frame;

FIG. 7 is a side elevational view of the mechanism shown in FIG. 5; and

FIG. 8 is a perspective view showing the link of the mechanism in FIGS. 6 and 7 upon which the check means is pivotally mounted.

Referring to the drawings and particularly FIGS. 1 and 2 thereof, a door return and check mechanism generally designated 10 is shown installed on a conventional door frame 12 and a door 14 pivotally mounted thereon by hinge 16 fastened by screws 18. The mechanism 10 includes an inner arm 20 and an outer arm 22 which are pivotally connected at 24 by a suitable connecting means such as the illustrated rivet. The inner end of the inner arm 20 is pivotally mounted at 26 to a bracket 28 comprising parallel upper and lower bracket members 29 and 30 each of which is secured to the door frame 12 by screws 32. A pin member 33 which may be a rivet as illustrated or similar connector, passes through the bracket members and the arm 20 with spacing washers 34 and 35 positioning the arm between the bracket members.

The outer arm 22 is pivotally attached at its outer end to bracket '36 by connector 38. Screws 39 secure the bracket '36 to the inner face of the door 14. The outer arm 22 is angularly configured in the region 40 a short distance towards the door from the pivot point 24 to permit the outer portion 42 of the outer arm 22 to parallel the inner arm 20 when the door is in the closed position illustrated in FIGS. 1 and 2. A portion 44 of the arm 22 extending inwardly from the pivot point 24 is pivotally joined at 45 by connector 46 to a parallel arm 47 which is maintained in parallel relation to the inner arm 20 by means of link 48. The arm 47 is pivotally connected to link 48 at 49 and the link 48 is connected to arm 20 at 50 in a similar manner. The link 48 is parallel to and of the same length as the portion 44 of arm 22 and hence the arm 47 will remain parallel with arm 20' at any position of the door between the closed position and the 180 open position as illustrated in FIG. 5.

A check means generally designated 52 comprising an adjustable spring-biased disc brake is incorporated into the mechanism. The brake includes a semi-circular portion 54 of the inner arm 20 located between the pivotal connection points 24 and 50 thereon, the portion 54 including a central hole therein through which extends the threaded reduced diameter end of a vertical brake shaft 56. A nut 58 on the under side of the arm 20 secures the shaft 56 to the arm. A generally circular brake lining 60 seated on the portion 54 of arm 20 has a central bore 62 through which the shaft 56 freely passes. A brake shoe 64- of a similar size and shape as the lining 60 overlies the lining and includes a bore 66 which pivotally accommodates the shaft 56. The lining 60 and shoe 64 include respective holes 68 and 70' which pass through radially protruding portions of those elements and which are aligned to receive the connector 72, in this instance a bolt, which pivotally attaches the shoe and lining to the parallel arm 47 at a point thereon corresponding to the location of the shaft 56 on arm 20 whereby movement of the parallel linkage will result in rotation of the brake lining and brake shoe with respect to the surface of the arm 20 and particularly the portion 54 thereof.

A coil spring 74 which in the embodiments illustrated is of a conical shape is seated on the brake shoe 64 around the shaft 56 and is compressed against the brake shoe by means of the wing nut 76 on the threaded upper end of the shaft 56. A suitable washer 77 is provided between the 'wing nut and the spring. It can readily be understood that the coil spring 74 in compression causes a frictional engagement of the brake lining 60 with the surface of the portion 54 of arm 20, thereby causing a braking effect on movement of the parallel linkage. By adjustment of the wing nut 76, the degree of braking efiect can be readily varied to suit the particular characteristics of the door.

A coil spring 78 extends in tension between an angled portion 80 of the arm 20 extending inwardly of the pivot 26 and a hole 82 in a protruding portion 84 of brake shoe 64 diametrically opposed from the hole 70 therein. The spring 78 extends parallel to and spaced from the inner arm 20. In the closed position of the door, the spring 78 is disposed above the outer portion 42 of the outer arm 22 by virtue of the offset 86 of the outer arm provided for this purpose.

For operation, the device is mounted as illustrated along a door and door frame by means of screws. The wing nut 76 is tightened to a trial position and the action of the door is observed. Should the checking action of the brake mechanism be insufiicient to prevent the slamming of the door, the wing nut 76 should be tightened to provide the desired checking effect. If on the other hand the checking action is such as to prevent the prompt closure of the door, the wing nut may be unscrewed to a setting at which the desired closure rate is obtained.

The nature of the parallel linkage and its relation to the inner and outer arms results in a maximum angular rotation of the brake shoe and lining with respect to the inner arm surface during the angular movement of the door just adjacent the closed position. Conversely, the relative rotation of the brake surfaces is minimal and is reduced almost to zero when the door is opened 180.

As a result, there is virtually no braking effect when the door is fully opened and a maximum braking effect as the door closely approaches the closed position. The reason for this can be understood by reference to the drawings. In FIG. 5 for example, with the door almost fully opened, the point of connection of the outer arm with the door will be seen to be moving in a direction substantially perpendicular to a line passing through the pivot point 26. The pivot point 24 at the end of the inner arm will of course at all times be moving perpendicular to a line between the point 24 and the pivot point 26. Therefore, the outer arm which links the pivot point 24 and the door by means of connector 38 will be rotating if at all only a very slight amount With respect to the inner arm 20. The amount of rotation of the inner and outer arms will of course determine and be equal to the rotation of the brake surfaces.

When the door is nearly at the closed position, there will be a relatively high degree of angular movement between the inner and outer arms and a correspondingly high degree of rotation of the brake surfaces, thereby maximizing the braking effect as the door approaches the door frame.

An important aspect of the invention is the over-center feature illustrated in FIG. 5 whereby when the pivot point 38 has passed over the center line 88 joining the pivot point 90 of the hinge 16 and the pivot point 26 of the inner end of the inner arm, then the spring 78 acts to urge the door toward the broken line position shown at 92 and will hold the door in the open position until it is manually moved back across the over-center position illustrated. This feature is extremely convenient when the door is to remain open for periods of time such as when packages are to be carried through the door.

In FIGS. 6-8, a modified embodiment of the invention is illustrated which is closely related to the embodiment previously described, the essential difference being the location of the parallel link on the door side of the inner arm, and the location of the brake shaft and pivotal mounting of the brake components on the parallel link. The mode of operation of the device is exactly the same as that previously described.

Referring to FIGS. 6-8, the modified embodiment generally designated 10' includes essentially the same elements as the embodiment previously described and accordingly these elements will bear corresponding identifying numerals with a prime designation. The parallel arm 47' as shown in FIG. 8 includes a semi-circular portion 98 to which the brake shaft 56' is axially connected. The check means 52' is accordingly mounted on the parallel arm 47' and the connector 73' passes through the inner arm 20'. The relation of the parallel arm and the inner arm are thus the reverse of that of the preceding embodiment as far as the check means is concerned although the brake action provided is identical.

In mounting the modified embodiment, the bracket 28' is positioned on the door frame 12 in spaced relation to the closed position of the door as necessitated by the reverse positions of the inner and parallel arms. The mode of operation of the modified embodiment and the method of adjustment thereof is identical with that previously described.

From the foregoing, it can be understod that the present invention provides an improved door return mechanism having a door checking means of a readily adjustable and simple structure. The provision of an over-center feature provides a positive door holding action when the door is fully opened. The simplicity of the device permits its economical manufacture and allows installation without special skills or tools.

Manifestly, changes in details of construction can be effected by those skilled in the art without departing from the spirit and the scope of the invention as defined in and limited solely by the appended claims.

I claim:

1. A door return and check mechanism for controlling the rate of return of a door pivotally mounted on a door frame, comprising an inner arm pivotally mounted to the door frame, an outer arm pivotally mounted to the outer end of said inner arm adjacent one end thereof and pivotally mounted to the door at the other end thereof, a parallel linkage adjacent one of said arms, said parallel linkage including a parallel arm pivotally connected to one of said arms, and a link pivotally connecting said parallel arm with the other of said arms, check means connected with said parallel linkage for restraining relative angular movement of said inner and outer arms, said check means comprising a disc brake, and spring means on said mechanism for urging the door toward the door frame.

2. A door return and check mechanism as claimed in claim 1 wherein said disc brake includes a brake spring for biasing the brake surfaces thereof, and means for adjusting the force applied by said brake spring and hence the checking action of said brake.

3. A door return and check mechanism as claimed in claim 1 wherein said parallel arm is pivotally connected to said outer arm, and wherein said link is pivotally connected to said inner arm, said parallel arm being parallel to and closely adjacent said inner arm.

4. A door return and check mechanism as claimed in claim 3 wherein said disc brake includes a brake surface on said inner arm, a brake shaft extending from said brake surface, a brake shoe pivotally mounted on said brake shaft, a coil spring mounted over said shaft engaging said brake shoe, a spring adjusting nut threadedly mounted on said brake shaft, and means connecting said brake shoe with said parallel arm to cause rotation of said shoe in response to movement of said parallel linkage.

5. A door return and check mechanism as claimed in claim 4 including a brake lining mounted between said brake shoe and said inner arm.

6. A door return and check mechanism as claimed in claim 4' wherein said spring means for urging the door toward the door frame comprises a tension coil spring connected between the inner end of said inner arm and a radially outwardly extending portion of said brake shoe diametrically opposed from said means connecting said brake shoe with said parallel arm.

7. A door return and check mechanism as claimed in claim 3 wherein said disc brake includes a brake surface .on said parallel arm, a brake shaft extending from said brake surface, a brake shoe pivotally mounted on said brake shaft, a coil spring mounted over said shaft engaging said brake shoe, a spring adjusting nut threadedly mounted on said brake shaft, and means connecting said brake shoe with said inner arm to cause rotation of said shoe in response to movement of said parallel linkage.

8. A door return and check mechanism as claimed in claim 7 including a brake lining mounted between said brake shoe and said inner arm.

9. A door return and check mechanism as claimed in claim 7 wherein said spring means for urging the door toward the door frame comprises a tension coil spring connected between the inner end of said inner arm and a radially outwardly extending portion of said brake shoe diametrically opposed from said means connecting said brake shoe with said inner arm.

10. A door return and check mechanism as claimed in claim 1 wherein said outer arm is angled to permit the outer portion thereof to parallel said inner arm when the door is in the closed position against the door frame.

11. A door return and check mechanism as claimed in claim 10 wherein the length of said inner and outer arms and the locations of their respective pivotal mountings on the door and door frame are such as to provide an over-center position of said mechanism at which said spring means acts to hold said door in the fully opened position.

12. A door return and check mechanism as claimed in claim 11 wherein said door in the fully opened position is substantially from the closed position.

References Qited UNITED STATES PATENTS 1,672,411 6/ 1928 Hamilton 16-65 2,089,408 8/1937 North 16-163 2,244,949 6/1941 Hutchinson 16-65X 2,720,676 10/1955 Vigmostad 16-163 FOREIGN PATENTS 745,033 2/ 1956 England 16-65 1,091,801 4/1955 France 16-48.5

BOBBY R. GAY, Primary Examiner P. A. ASCHENBRENNER, Assistant Examiner US. Cl. X.R. 16-80, 163 

